1. Field of the Invention
The present invention relates to a microorganism that belongs to the genus Corynebacterium and has enhanced L-lysine productivity and a method of producing L-lysine using the same.
2. Description of the Related Art
A strain of the genus Corynebacterium, particularly Corynebacterium glutamicum, is a microorganism which is extensively used to produce L-amino acid. L-amino acid, particularly L-lysine, is used to produce feed for animals and medicines for humans, and is also used in the pharmaceutics industry. L-amino acid is produced through the fermentation of the Corynebacterium strain, but since the method by which L-amino acid is produced using the genus Corynebacterium is important, there have been extensive attempts to improve the method.
One such attempt to improve L-amino acid production using a strain of the genus Corynebacterium involves destroying or attenuating the expression of a specific gene using recombinant DNA technology. For example, in U.S. Pat. No. 6,872,553, there is provided a process for the fermentative preparation of L-amino acids, the process including a) a growing stage of the Corynebacterium in which DNA encoding of phosphoenol pyruvate (PEP) carboxykinase (pck) is attenuated by a method of mutagenesis selected from the group consisting of insertion mutagenesis by insertion of at least one base pair, deletion mutagenesis with deletion of at least one base pair, and transition or transversion mutagenesis with incorporation of a non-sense mutation of the activity of said polypeptide is reduced as compared to an unattenuated Corynebacterium; b) a concentrating stage of the desired L-amino acid product in the medium or cells of said bacteria; and c) an isolating stage of separating said L-amino acid product.
Also, there has been extensive research into the effects of amplifying genes which relate to the biosynthesis of individual L-amino acid on the production of L-amino acid, and into the improvement of the L-amino acid producing Corynebacterium strain (Eggeling, Amino Acids 6, 261-272 (1994).) In addition, there have been attempts to introduce a foreign gene of different bacterial origin. For example, in Japanese Published Application No. Hei 7-121228, there is provided a process of culturing a microorganism which belongs to the genus Corynebacterium or the genus Brevibacterium and possesses a DNA fragment having gene information related to the synthesis of citric acid synthase of a microorganism and recombinant DNA of vector DNA, and a method of producing L-glutamic acids and L-proline in the medium.
However, according to said methods, the use of a strain having enhanced L-lysine productivity is desired.